Showing posts with label black. Show all posts
Showing posts with label black. Show all posts

Thursday, December 10, 2015

How I Shot It: After the Rain

How I Shot It: After the Rain

This photo got a 1st Place in November’s Enchanted Lens Camera Club competition Group A Assigned Digital category, which was Motion Blur/Out of Focus, judged by Dana Foy.



Camera Info
GoPro Hero 3+ Black Edition
Lens: 15mm
Exposure mode: Hacked, explained below
Exposure: ISO 100, f 2.8, 2.7 seconds
White balance: Auto

Lighting
Ambient fluorescent, sodium, LED, halogen, incandescent

Other Gear
GoPro Suction Cup Mount
GoPro Waterproof Case
My car

Goal

To show motion, I wanted to do some night car photography, but not the typical taillights-on-a-highway scene. I figured that a a lot of entries would be that type of shot, so I wanted to kind of reverse the concept by having the car be the static object and the scenery in motion. Turns out, this one was the only car light trails shot entered, I think.

Method

I initially wanted the camera mounted on the hood, aimed at me with the lights and reflections all kind of pointing toward the center of the frame. 

I thought I could mount my tripod to the grill of the car with some cargo straps. I did some experiments with my tripod with the car was in the garage, and couldn’t come up with a way to secure it well enough to be confident that it would hold the camera securely.

I had a GoPro and a suction cup mount, but the GoPro has very limited exposure settings. I needed some long exposure times, and the GoPro is not designed to do that type of thing. So I hit the internet and found some stuff where people had hacked a GoPro to do long-exposure stuff. I wrote about it in my last post.

With the above hack installed on the memory card, I mounted the GoPro on the hood with the Suction Cup Mount. I set the camera to start taking pictures, and drove down to SR 550 in Bernalillo.

I returned home and pulled the pics off the GoPro. Turned out that they were boring.


The next night, I put the camera on the driver’s door of the car, way down low. This made me a little nervous, because if the camera fell off, there was a good chance I would run over it with the rear wheel, or it would bounce into oncoming traffic. It held on fine until I was making the turn into the driveway, where I heard it fall off onto the concrete. The waterproof case got scuffed up, but at least the lens window was undamaged. Whew!

Post-processing





During the run, the GoPro took about 250 pictures. I loaded them into Lightroom and picked the best ones. I settled on 3 that had the most interesting lights. I toyed around with the Basic sliders to recover blown highlights, lighten the shadows, and boost the vibrance and saturation to give some bright colors to liven up the images. Then I copied the settings from one picture to another.

Opening the 3 photos as layers in Photoshop, I ran the Auto Align Layers function. I tried a bunch of different transparency settings and opacity amounts to see what gave the most interesting arrangement. While doing this, I also tried arranging the layers in different ways. 

When I was happy with the general arrangement, I added layer masks to the top 2 layers, and masked out places with a soft brush. Most of the problems were areas where the brightest areas coincided, such as the headlights of oncoming cars. These highlights were very bright, so those got the most attention.


I then flattened and saved the file, returning to Lightroom. The only adjustment that made it into the final edit was taking the Blacks to +100. I tried sharpening the image, but it actually detracted from the image. I remembered that the assignment was to produce blur.

Analysis


It was a fun picture to make. And I learned that a GoPro can be hacked! 

I find it interesting what you can see in long exposures that you don’t see with the naked eye. LED signs produce very intense light, and they pulse rapidly. Fluorescent lights also pulse with the 60 Hertz cycle of the US electrical grid. You can see this effect in the top left quadrant of the photo if you look for the McDonald’s sign.  

You probably don’t think about it much when driving, but even on the smoothest pavement, a car’s suspension is constantly working. If you look closely, the wheel of my car is moving up and down a little bit.

What I like about the picture is that there is so little that is familiar and in sharp focus, but once you see the fender of the car and figure out what is going on, it all seems to fall in place and the rest makes sense. 

Technically, despite my work in Photoshop, there is still lost detail in the highlights. Pixel-peepers may howl at that, but in a photo like this, blown highlights might actually add to the impact of the photo as I think it imparts an energetic feeling. Besides, with the goal of “blur” in the assignment, detail must be inherently lost, anyway.

Tips
If you try this type of shot, make very sure that your camera is mounted securely. I drove at about 40 MPH while making this photo. 40 MPH doesn’t seem like it’s very fast when you’re driving a car, but imagine your camera on a tripod in a 40 MPH wind. And then factor for the additional bumping, vibration, and G-forces that your car endures while driving. If I were to do it again, I would add a safety string to the GoPro to keep it from hitting the ground if it were to fall off.

I would love to hear comments and/or questions!


Saturday, October 24, 2015

Hacking a GoPro Hero3+ Black to take long exposures

I wanted to make a photo for our photo club’s monthly assignment with a long exposure by attaching my GoPro Hero3+ Black on the hood of my car with the Suction Cup mount. 

The problem was that the Hero3+ Black (I’ll call it “H3+B” from here on) tries to shorten the exposure time as much as it can by increasing the ISO, which is the opposite of what I needed it to do. I wanted to keep the ISO low, and increase the shutter open time to a few seconds to get light smears.

I searched DuckDuckGo for a solution and found this page (https://gist.github.com/KonradIT/ce55b04ab4ad10592ebf/#file-autoexechack-md) by Konrad Iturbe. 

Konrad has worked out an autoexec.ash boot script that is copied to the top level of the MicroSD card  for the H3+B. He also lists a table of values that are put in the script at the X and Y values that determine the shutter speed in seconds.

How-To when using a Mac:

What you need:

GoPro Hero3+ Black. Some people have had some success with Hero3+ Silvers and Hero2’s as well, but I don’t own any of those. Some or all of these older cameras may need a modified version of the script.

A MicroSD card from SanDisk, Lexar, or Delkin. According to Konrad's site, not all cards can support this hack, but I wonder about that since I tried a Kingston 16GB card and it worked fine. Check Konrad’s site for a list of known working cards. I think the key issue that many people have is that the autoexec.ash file isn't saved properly in UNIX format.

A MicroSD card adapter, and a card reader of some type. If you have a MicroSD card, it should have come with an adapter to fit a standard-sized SD slot. Again, reports are that not all card readers seem to work properly. I’m using an old Griffin Simplifi from 2007. It works fine for me. I doubt that the card reader is much of a factor, but I've seen bizarre stuff happen with cheap hardware over the years. 

A text editor that can save the text file as UNIX format. This is VERY important! I’m on a Mac running OS X 10.11, and I tried TextEdit and BBEdit 10.5.13, neither of which worked no matter how I twiddled with the Save dialogs.

If the file is not in UNIX format, it will be ignored when the camera boots. Instead, I used nano, which is installed with all recent versions of Mac OS X. Worked like a champ, and it's free.

Here we go!

Step 1: Set the GoPro to have the power-on default mode to be the Single Still Image mode, which is the icon of just the camera, not the time-lapse one. Shut the camera off, and remove the SD card. Put the SD card in your computer.

Step 2: Open the Terminal program. It is in Applications > Utilities. A window like this will open.




Step 3: Type (or copy and paste) the following command into the Terminal window.

nano ~/Desktop/autoexec.ash




and press Return. This will start the nano editor and create an empty text file on your Desktop called autoexec.ash.

Step 4: Copy this code and paste it into nano in the Terminal window. 

t app appmode photo
sleep 1
t ia2 -ae still_exp P X Y
sleep 1
t app button shutter PR
sleep A
d:\autoexec.ash
REBOOT yes




Step 5: You will be editing lines 3 and 6. Using the arrow keys on the keyboard (nano doesn’t respond to mouse movements), navigate the blinking cursor up to line 3 and over to the P character. Delete the P, and enter the ISO you want the GoPro to use. I entered 100.

Step 6: Next, navigate to the X in the same line, and delete it. In its place, I entered 55, which translates to about 6 seconds of exposure time. 

Step 7: The Y value is supposed to be the lens aperture, but GoPros have fixed apertures, which is 2.8 on the H3+B. Delete the Y character, and enter the same value that you did for the X. For some reason, both the X and Y values need to be the same.

Step 8: Using the arrow keys, navigate down to line 6. Delete the A, and replace it with a value in seconds that you want between exposures. I used 9 seconds.

Except for saving the file, you’re done. Here’s what my nano window looks like.




Step 9: Check over your values and make sure you didn’t add any blank lines to the script. When ready, press Ctrl-X. The bottom of the nano window will read “Save modified buffer (ANSWERING "No" WILL DESTROY CHANGES) ?” Press Y, and then, if you are happy with the name of the file, press Return. This will save the file and close nano.

Step 10: Go back to the Finder, and drag the newly modified autoexec.ash file to the SD card. Put the file in the top (root) level of the SD card, like this: 


Step 11: Eject the SD card from your computer. Put the SD card in the GoPro and power it up. When the camera comes up, it will take one picture with your ISO and shutter speed changes, and then reboot the camera and take another picture. It will keep doing this until you power the camera off again.

Tips

The P value is the ISO setting. Use 100, 200, or 400 to get less noise in your images. 

The A value is the shot interval amount in seconds. In use, the actual time between shots seems to be longer than the value entered because there is some time added due to the script rebooting the GoPro. I think the time is from the moment when the exposure starts to the start of the reboot. If your exposure is 5 seconds, and A is set to 4 seconds, I’m not sure what would happen. Remember that the camera needs some amount of time to write the picture to the memory card. Also, if you want to stop the camera and the interval is too short, you might have a hard time getting the camera to stop. As I play with this, I’ll see if I can figure out what a minimal setting would be.

The X and Y values determine the shutter speed. Values range between 2 (8.5 seconds) and 1000 (0.000158328 seconds). Below is a table copied from Konrad’s site. In the right column, the Exposure Times are in European format, which uses commas as decimal points instead of the American style of using periods. So if you are in the US, read 8,5 as 8.5.


Value (number to write in hack file)Exposure Time (seconds)
28,5
57,7
157,3
207,1
256,9
306,8
396,4
406,3
456,2
506,1
755,3
855
954,7
994,6
1004,6
1303,9
1603,3
2002,7
2552
4001
5000,56
6000,33333
10000,000158328

If you don't want to go through editing autoexec.ash files, Edward Czajka has a collection of pre-configured files that you can download through DropBox. It's here: http://edwardczajka.blogspot.com/2015/06/long-time-lapse-exposures-with-gopro.html

How to return the camera to normal operation

There are two ways to get your camera back to it’s normal configuration. One way is to format the memory card while it’s in the camera. This will delete the autoexec.ash file, and it will also delete all your pictures on the card, too. So think carefully before doing this!

The other way is to delete or rename the autoexec.ash file from the memory card manually using your computer. I’ve read that some people with an Android phone and a compatible card reader have done this. 

Alternatively, and probably easiest, you could carry two memory cards, one with the autoexec.ash file, and another one without it. Switch out the cards in the camera as you need.

Will it damage the GoPro?

Probably not. The script seems to just direct the camera as to what to do at boot. But of course, this is a non-official hack, so if something goes wrong, don't blame me. 


Results

Here's a picture I tried. ISO 100, 3.3 seconds (X & Y setting of 160).
It's been cropped in Lightroom.